From 746f1e558bc52b9693c1a1ecdab60f8392e5ff18 Mon Sep 17 00:00:00 2001 From: Michael Halcrow Date: Wed, 23 Jul 2008 21:30:02 -0700 Subject: eCryptfs: Privileged kthread for lower file opens eCryptfs would really like to have read-write access to all files in the lower filesystem. Right now, the persistent lower file may be opened read-only if the attempt to open it read-write fails. One way to keep from having to do that is to have a privileged kthread that can open the lower persistent file on behalf of the user opening the eCryptfs file; this patch implements this functionality. This patch will properly allow a less-privileged user to open the eCryptfs file, followed by a more-privileged user opening the eCryptfs file, with the first user only being able to read and the second user being able to both read and write. eCryptfs currently does this wrong; it will wind up calling vfs_write() on a file that was opened read-only. This is fixed in this patch. Signed-off-by: Michael Halcrow Cc: Dave Kleikamp Cc: Serge Hallyn Cc: Eric Sandeen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ecryptfs/ecryptfs_kernel.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'fs/ecryptfs/ecryptfs_kernel.h') diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index c15c25745e0..b4a0cccfdd7 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -559,6 +559,20 @@ extern struct kmem_cache *ecryptfs_key_record_cache; extern struct kmem_cache *ecryptfs_key_sig_cache; extern struct kmem_cache *ecryptfs_global_auth_tok_cache; extern struct kmem_cache *ecryptfs_key_tfm_cache; +extern struct kmem_cache *ecryptfs_open_req_cache; + +struct ecryptfs_open_req { +#define ECRYPTFS_REQ_PROCESSED 0x00000001 +#define ECRYPTFS_REQ_DROPPED 0x00000002 +#define ECRYPTFS_REQ_ZOMBIE 0x00000004 + u32 flags; + struct file **lower_file; + struct dentry *lower_dentry; + struct vfsmount *lower_mnt; + wait_queue_head_t wait; + struct mutex mux; + struct list_head kthread_ctl_list; +}; int ecryptfs_interpose(struct dentry *hidden_dentry, struct dentry *this_dentry, struct super_block *sb, @@ -690,5 +704,10 @@ void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx); int ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, uid_t euid, struct user_namespace *user_ns, struct pid *pid); +int ecryptfs_init_kthread(void); +void ecryptfs_destroy_kthread(void); +int ecryptfs_privileged_open(struct file **lower_file, + struct dentry *lower_dentry, + struct vfsmount *lower_mnt); #endif /* #ifndef ECRYPTFS_KERNEL_H */ -- cgit v1.2.3-70-g09d2 From 72b55fffd631a89e5be6fe1b4f2565bc4cd90deb Mon Sep 17 00:00:00 2001 From: Michael Halcrow Date: Wed, 23 Jul 2008 21:30:07 -0700 Subject: eCryptfs: do not try to open device files on mknod When creating device nodes, eCryptfs needs to delay actually opening the lower persistent file until an application tries to open. Device handles may not be backed by anything when they first come into existence. [Valdis.Kletnieks@vt.edu: build fix] Signed-off-by: Michael Halcrow Cc: Signed-off-by: Linus Torvalds --- fs/ecryptfs/ecryptfs_kernel.h | 6 +++++- fs/ecryptfs/file.c | 14 ++++++++++++++ fs/ecryptfs/inode.c | 6 ++++-- fs/ecryptfs/main.c | 29 +++++++++++++++++++---------- 4 files changed, 42 insertions(+), 13 deletions(-) (limited to 'fs/ecryptfs/ecryptfs_kernel.h') diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index b4a0cccfdd7..b0727f91454 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -235,6 +235,7 @@ struct ecryptfs_crypt_stat { #define ECRYPTFS_METADATA_IN_XATTR 0x00000100 #define ECRYPTFS_VIEW_AS_ENCRYPTED 0x00000200 #define ECRYPTFS_KEY_SET 0x00000400 +#define ECRYPTFS_DELAY_PERSISTENT 0x00000800 u32 flags; unsigned int file_version; size_t iv_bytes; @@ -574,9 +575,11 @@ struct ecryptfs_open_req { struct list_head kthread_ctl_list; }; +#define ECRYPTFS_INTERPOSE_FLAG_D_ADD 0x00000001 +#define ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE 0x00000002 int ecryptfs_interpose(struct dentry *hidden_dentry, struct dentry *this_dentry, struct super_block *sb, - int flag); + u32 flags); int ecryptfs_fill_zeros(struct file *file, loff_t new_length); int ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat, const char *name, int length, @@ -709,5 +712,6 @@ void ecryptfs_destroy_kthread(void); int ecryptfs_privileged_open(struct file **lower_file, struct dentry *lower_dentry, struct vfsmount *lower_mnt); +int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry); #endif /* #ifndef ECRYPTFS_KERNEL_H */ diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index f0be2905152..2c2d60df3f6 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -199,6 +199,20 @@ static int ecryptfs_open(struct inode *inode, struct file *file) "file must hence be opened RO\n", __func__); goto out; } + if (!ecryptfs_inode_to_private(inode)->lower_file) { + BUG_ON(!(crypt_stat->flags & ECRYPTFS_DELAY_PERSISTENT)); + mutex_lock(&crypt_stat->cs_mutex); + crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); + mutex_unlock(&crypt_stat->cs_mutex); + rc = ecryptfs_init_persistent_file(ecryptfs_dentry); + if (rc) { + printk(KERN_ERR "%s: Error attempting to initialize " + "the persistent file for the dentry with name " + "[%s]; rc = [%d]\n", __func__, + ecryptfs_dentry->d_name.name, rc); + goto out; + } + } ecryptfs_set_file_lower( file, ecryptfs_inode_to_private(inode)->lower_file); if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index 7315547193e..26090878c93 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -308,7 +308,8 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry, d_add(dentry, NULL); goto out; } - rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1); + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, + ECRYPTFS_INTERPOSE_FLAG_D_ADD); if (rc) { ecryptfs_printk(KERN_ERR, "Error interposing\n"); goto out_dput; @@ -537,7 +538,8 @@ ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); if (rc || !lower_dentry->d_inode) goto out; - rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, + ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE); if (rc) goto out; fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index 10475d93ff5..ee4f84b2041 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -117,7 +117,7 @@ void __ecryptfs_printk(const char *fmt, ...) * * Returns zero on success; non-zero otherwise */ -static int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry) +int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry) { struct ecryptfs_inode_info *inode_info = ecryptfs_inode_to_private(ecryptfs_dentry->d_inode); @@ -149,14 +149,14 @@ static int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry) * @lower_dentry: Existing dentry in the lower filesystem * @dentry: ecryptfs' dentry * @sb: ecryptfs's super_block - * @flag: If set to true, then d_add is called, else d_instantiate is called + * @flags: flags to govern behavior of interpose procedure * * Interposes upper and lower dentries. * * Returns zero on success; non-zero otherwise */ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry, - struct super_block *sb, int flag) + struct super_block *sb, u32 flags) { struct inode *lower_inode; struct inode *inode; @@ -193,7 +193,7 @@ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry, init_special_inode(inode, lower_inode->i_mode, lower_inode->i_rdev); dentry->d_op = &ecryptfs_dops; - if (flag) + if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD) d_add(dentry, inode); else d_instantiate(dentry, inode); @@ -201,12 +201,21 @@ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry, /* This size will be overwritten for real files w/ headers and * other metadata */ fsstack_copy_inode_size(inode, lower_inode); - rc = ecryptfs_init_persistent_file(dentry); - if (rc) { - printk(KERN_ERR "%s: Error attempting to initialize the " - "persistent file for the dentry with name [%s]; " - "rc = [%d]\n", __func__, dentry->d_name.name, rc); - goto out; + if (!(flags & ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE)) { + rc = ecryptfs_init_persistent_file(dentry); + if (rc) { + printk(KERN_ERR "%s: Error attempting to initialize " + "the persistent file for the dentry with name " + "[%s]; rc = [%d]\n", __func__, + dentry->d_name.name, rc); + goto out; + } + } else { + struct ecryptfs_inode_info *inode_info = + ecryptfs_inode_to_private(dentry->d_inode); + + inode_info->lower_file = NULL; + inode_info->crypt_stat.flags |= ECRYPTFS_DELAY_PERSISTENT; } out: return rc; -- cgit v1.2.3-70-g09d2 From 391b52f98cf2e9bff227dad8bf9ea206fec43fa4 Mon Sep 17 00:00:00 2001 From: Michael Halcrow Date: Wed, 23 Jul 2008 21:30:08 -0700 Subject: eCryptfs: Make all persistent file opens delayed There is no good reason to immediately open the lower file, and that can cause problems with files that the user does not intend to immediately open, such as device nodes. This patch removes the persistent file open from the interpose step and pushes that to the locations where eCryptfs really does need the lower persistent file, such as just before reading or writing the metadata stored in the lower file header. Two functions are jumping to out_dput when they should just be jumping to out on error paths. This patch also fixes these. Signed-off-by: Michael Halcrow Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ecryptfs/ecryptfs_kernel.h | 2 -- fs/ecryptfs/file.c | 4 ---- fs/ecryptfs/inode.c | 27 +++++++++++++++++++++++---- fs/ecryptfs/main.c | 16 ---------------- 4 files changed, 23 insertions(+), 26 deletions(-) (limited to 'fs/ecryptfs/ecryptfs_kernel.h') diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index b0727f91454..b73fb752c5f 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -235,7 +235,6 @@ struct ecryptfs_crypt_stat { #define ECRYPTFS_METADATA_IN_XATTR 0x00000100 #define ECRYPTFS_VIEW_AS_ENCRYPTED 0x00000200 #define ECRYPTFS_KEY_SET 0x00000400 -#define ECRYPTFS_DELAY_PERSISTENT 0x00000800 u32 flags; unsigned int file_version; size_t iv_bytes; @@ -576,7 +575,6 @@ struct ecryptfs_open_req { }; #define ECRYPTFS_INTERPOSE_FLAG_D_ADD 0x00000001 -#define ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE 0x00000002 int ecryptfs_interpose(struct dentry *hidden_dentry, struct dentry *this_dentry, struct super_block *sb, u32 flags); diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index 2c2d60df3f6..9244d653743 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -200,10 +200,6 @@ static int ecryptfs_open(struct inode *inode, struct file *file) goto out; } if (!ecryptfs_inode_to_private(inode)->lower_file) { - BUG_ON(!(crypt_stat->flags & ECRYPTFS_DELAY_PERSISTENT)); - mutex_lock(&crypt_stat->cs_mutex); - crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); - mutex_unlock(&crypt_stat->cs_mutex); rc = ecryptfs_init_persistent_file(ecryptfs_dentry); if (rc) { printk(KERN_ERR "%s: Error attempting to initialize " diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index 26090878c93..d755455e3bf 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -189,6 +189,16 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry) "context; rc = [%d]\n", rc); goto out; } + if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) { + rc = ecryptfs_init_persistent_file(ecryptfs_dentry); + if (rc) { + printk(KERN_ERR "%s: Error attempting to initialize " + "the persistent file for the dentry with name " + "[%s]; rc = [%d]\n", __func__, + ecryptfs_dentry->d_name.name, rc); + goto out; + } + } rc = ecryptfs_write_metadata(ecryptfs_dentry); if (rc) { printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); @@ -312,7 +322,7 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry, ECRYPTFS_INTERPOSE_FLAG_D_ADD); if (rc) { ecryptfs_printk(KERN_ERR, "Error interposing\n"); - goto out_dput; + goto out; } if (S_ISDIR(lower_inode->i_mode)) { ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n"); @@ -338,11 +348,21 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry, rc = -ENOMEM; ecryptfs_printk(KERN_ERR, "Cannot ecryptfs_kmalloc a page\n"); - goto out_dput; + goto out; } crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) ecryptfs_set_default_sizes(crypt_stat); + if (!ecryptfs_inode_to_private(dentry->d_inode)->lower_file) { + rc = ecryptfs_init_persistent_file(dentry); + if (rc) { + printk(KERN_ERR "%s: Error attempting to initialize " + "the persistent file for the dentry with name " + "[%s]; rc = [%d]\n", __func__, + dentry->d_name.name, rc); + goto out; + } + } rc = ecryptfs_read_and_validate_header_region(page_virt, dentry->d_inode); if (rc) { @@ -538,8 +558,7 @@ ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); if (rc || !lower_dentry->d_inode) goto out; - rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, - ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE); + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); if (rc) goto out; fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index ee4f84b2041..6f403cfba14 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -201,22 +201,6 @@ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry, /* This size will be overwritten for real files w/ headers and * other metadata */ fsstack_copy_inode_size(inode, lower_inode); - if (!(flags & ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE)) { - rc = ecryptfs_init_persistent_file(dentry); - if (rc) { - printk(KERN_ERR "%s: Error attempting to initialize " - "the persistent file for the dentry with name " - "[%s]; rc = [%d]\n", __func__, - dentry->d_name.name, rc); - goto out; - } - } else { - struct ecryptfs_inode_info *inode_info = - ecryptfs_inode_to_private(dentry->d_inode); - - inode_info->lower_file = NULL; - inode_info->crypt_stat.flags |= ECRYPTFS_DELAY_PERSISTENT; - } out: return rc; } -- cgit v1.2.3-70-g09d2